Author: enrico
Date: Mon Jan 27 15:31:26 2014
New Revision: 200247
URL: http://llvm.org/viewvc/llvm-project?rev=200247&view=rev
Log:
<rdar://problem/15776874>
ValueObjectPrinter could enter an infinite loop while trying to display an
aptly formed ValueObject: a reference, with a child of some pointer type, such
that the pointees chain ended up pointing back to some part of itself - a
pointer to itself being the simplest such case
Fixed here by only setting a pointer depth when needed, and ensuring that we
won't overflow and wrap the pointer depth when it's zero.
Added:
lldb/trunk/test/functionalities/data-formatter/refpointer-recursion/
lldb/trunk/test/functionalities/data-formatter/refpointer-recursion/Makefile
lldb/trunk/test/functionalities/data-formatter/refpointer-recursion/TestDataFormatterRefPtrRecursion.py
lldb/trunk/test/functionalities/data-formatter/refpointer-recursion/main.cpp
Modified:
lldb/trunk/source/DataFormatters/ValueObjectPrinter.cpp
Modified: lldb/trunk/source/DataFormatters/ValueObjectPrinter.cpp
URL:
http://llvm.org/viewvc/llvm-project/lldb/trunk/source/DataFormatters/ValueObjectPrinter.cpp?rev=200247&r1=200246&r2=200247&view=diff
==============================================================================
--- lldb/trunk/source/DataFormatters/ValueObjectPrinter.cpp (original)
+++ lldb/trunk/source/DataFormatters/ValueObjectPrinter.cpp Mon Jan 27 15:31:26
2014
@@ -403,7 +403,6 @@ ValueObjectPrinter::ShouldPrintChildren
// Use a new temporary pointer depth in case we override the
// current pointer depth below...
- uint32_t curr_ptr_depth = m_ptr_depth;
if (is_ptr || is_ref)
{
@@ -413,7 +412,7 @@ ValueObjectPrinter::ShouldPrintChildren
if (m_valobj->GetPointerValue (&ptr_address_type) == 0)
return false;
- else if (is_ref && m_curr_depth == 0)
+ else if (is_ref && m_curr_depth == 0 && curr_ptr_depth == 0)
{
// If this is the root object (depth is zero) that we are
showing
// and it is a reference, and no pointer depth has been
supplied
@@ -468,7 +467,7 @@ ValueObjectPrinter::PrintChild (ValueObj
ValueObjectPrinter child_printer(child_sp.get(),
m_stream,
child_options,
- (IsPtr() || IsRef()) ? curr_ptr_depth
- 1 : curr_ptr_depth,
+ (IsPtr() || IsRef()) &&
curr_ptr_depth >= 1 ? curr_ptr_depth - 1 : curr_ptr_depth,
m_curr_depth + 1);
child_printer.PrintValueObject();
}
Added:
lldb/trunk/test/functionalities/data-formatter/refpointer-recursion/Makefile
URL:
http://llvm.org/viewvc/llvm-project/lldb/trunk/test/functionalities/data-formatter/refpointer-recursion/Makefile?rev=200247&view=auto
==============================================================================
---
lldb/trunk/test/functionalities/data-formatter/refpointer-recursion/Makefile
(added)
+++
lldb/trunk/test/functionalities/data-formatter/refpointer-recursion/Makefile
Mon Jan 27 15:31:26 2014
@@ -0,0 +1,5 @@
+LEVEL = ../../../make
+
+CXX_SOURCES := main.cpp
+
+include $(LEVEL)/Makefile.rules
Added:
lldb/trunk/test/functionalities/data-formatter/refpointer-recursion/TestDataFormatterRefPtrRecursion.py
URL:
http://llvm.org/viewvc/llvm-project/lldb/trunk/test/functionalities/data-formatter/refpointer-recursion/TestDataFormatterRefPtrRecursion.py?rev=200247&view=auto
==============================================================================
---
lldb/trunk/test/functionalities/data-formatter/refpointer-recursion/TestDataFormatterRefPtrRecursion.py
(added)
+++
lldb/trunk/test/functionalities/data-formatter/refpointer-recursion/TestDataFormatterRefPtrRecursion.py
Mon Jan 27 15:31:26 2014
@@ -0,0 +1,56 @@
+"""
+Test that ValueObjectPrinter does not cause an infinite loop when a reference
to a struct that contains a pointer to itself is printed.
+"""
+
+import os, time
+import unittest2
+import lldb
+from lldbtest import *
+import lldbutil
+
+class DataFormatterRefPtrRecursionTestCase(TestBase):
+
+ mydir = TestBase.compute_mydir(__file__)
+
+ @unittest2.skipUnless(sys.platform.startswith("darwin"), "requires Darwin")
+ @dsym_test
+ def test_with_dsym_and_run_command(self):
+ """Test that ValueObjectPrinter does not cause an infinite loop when a
reference to a struct that contains a pointer to itself is printed."""
+ self.buildDsym()
+ self.data_formatter_commands()
+
+ @dwarf_test
+ def test_with_dwarf_and_run_command(self):
+ """Test that ValueObjectPrinter does not cause an infinite loop when a
reference to a struct that contains a pointer to itself is printed."""
+ self.buildDwarf()
+ self.data_formatter_commands()
+
+ def setUp(self):
+ # Call super's setUp().
+ TestBase.setUp(self)
+ # Find the line number to break at.
+ self.line = line_number('main.cpp', '// Set break point at this line.')
+
+ def data_formatter_commands(self):
+ """Test that ValueObjectPrinter does not cause an infinite loop when a
reference to a struct that contains a pointer to itself is printed."""
+ self.runCmd("file a.out", CURRENT_EXECUTABLE_SET)
+
+ lldbutil.run_break_set_by_file_and_line (self, "main.cpp", self.line,
num_expected_locations=1, loc_exact=True)
+
+ self.runCmd("run", RUN_SUCCEEDED)
+
+ # The stop reason of the thread should be breakpoint.
+ self.expect("thread list", STOPPED_DUE_TO_BREAKPOINT,
+ substrs = ['stopped',
+ 'stop reason = breakpoint'])
+
+ self.expect("frame variable foo", substrs = []);
+ self.expect("frame variable foo --ptr-depth=1", substrs = ['ID = 1']);
+ self.expect("frame variable foo --ptr-depth=2", substrs = ['ID = 1']);
+ self.expect("frame variable foo --ptr-depth=3", substrs = ['ID = 1']);
+
+if __name__ == '__main__':
+ import atexit
+ lldb.SBDebugger.Initialize()
+ atexit.register(lambda: lldb.SBDebugger.Terminate())
+ unittest2.main()
Added:
lldb/trunk/test/functionalities/data-formatter/refpointer-recursion/main.cpp
URL:
http://llvm.org/viewvc/llvm-project/lldb/trunk/test/functionalities/data-formatter/refpointer-recursion/main.cpp?rev=200247&view=auto
==============================================================================
---
lldb/trunk/test/functionalities/data-formatter/refpointer-recursion/main.cpp
(added)
+++
lldb/trunk/test/functionalities/data-formatter/refpointer-recursion/main.cpp
Mon Jan 27 15:31:26 2014
@@ -0,0 +1,21 @@
+int _ID = 0;
+
+class Foo {
+ public:
+ Foo *next;
+ int ID;
+
+ Foo () : next(0), ID(++_ID) {}
+};
+
+int evalFoo(Foo& foo)
+{
+ return foo.ID; // Set break point at this line.
+}
+
+int main() {
+ Foo f;
+ f.next = &f;
+ return evalFoo(f);
+}
+
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